Liquid media may be transported in a wind turbine for a number of reasons. For example, a liquid medium may be part of a heating-system for the wind turbine or for other parts of the wind turbine.
U.S. Pat. No. 7,168,251 discloses a wind energy turbine with a unit to be cooled by a cooling medium (gas or liquid) flowing in a cooling circuit from said unit to a heat exchanger. The unit to be cooled is arranged in the tower or in the nacelle of the wind energy turbine. The heat exchanger is located outside of the tower or the nacelle and is configured to be cooled by ambient air. In one embodiment, the cooling components are used in a closed-loop cooling circuit with a liquid cooling medium, for example water. A pump or similar element is also arranged in the cooling circuit.
U.S. Pat. No. 6,520,737 discloses an offshore wind turbine, wherein a power transmission in a nacelle is cooled by means of a liquid conducted to the nacelle from a tower on which the nacelle is pivotally arranged around a vertical yawing axis. A device is shown for forming one or more passageways for liquid between the nacelle and the tower during most yaw positions of the nacelle.
Regarding other liquids, in particular any liquid medium required in the hub, for example lubricating oil for use in bearings or hydraulic systems, liquids for blade defrosting etc., in the prior art such liquid media are only transported intermittently in batches. A liquid medium is first stored in a transport vessel or container, lifted into the nacelle by cranes or hoists and manually distributed there by maintenance staff. Obviously, such a manual distribution of the liquid media is time-consuming and expensive.